Portability is now a very critical factor in such an optical apparatus as a digital still camera, and attempts to decrease the size and weight of a zoom lens, which is a camera lens, is progressing in order to decrease the size, thickness and weight of a camera main unit. However it is difficult to hold such a camera, and a slight movement of a camera during photographing (e.g. slight motion of a camera generated when the user presses a release button) causes image blurring during exposure, which deteriorates the image quality. To solve this problem, a zoom lens, where a detection system for detecting a slight motion of a camera, a computing system for controlling a shift lens group according to the value that is output from the detection system, and a drive system for shifting the shift lens group, are combined, and the image blurring is corrected by driving the shift lens group so as to compensate the image blurring caused by the slight motion of the camera, has been disclosed (e.g. Japanese Patent Application Laid-Open No. 2005-128186).